Description

Key Characters:

Growth Form: Perennial herbs with a strong sweet scent.

Stems: Stems 3–10 dm long.

Roots:

Leaves: Leaves simple. Opposite. Blades lanceolate to broadly lanceolate, (30–)50–90 mm long, (7–)15–30 mm wide. Surfaces usually glabrous, sometimes sparsely villous on petioles and veins of lower surface, the hairs simple or branched, Surfaces smooth or slightly rugose. Margins serrate. Subsessile. Stipules absent.

Flowers: Flowers small, in closely spaced, terminal verticillasters, these arranged in spike-like inflorescences 5–10 mm in diameter at anthesis, each flower +/- bracteolate. Calyx actinomorphic, campanulate, 10-nerved, 5-toothed, the teeth +/- equal, 1–3 mm long, glabrous to pubescent, splitting longitudinally, usually persistent or sometimes only ventral 1/2 persistent. Corolla zygomorphic, slightly bilabiate, funnelform to campanulate, lilac, pink, or white, 2–4 mm long; nectary disk often present at base of ovary, annular or developed on anterior side only. Stamens 4, equal, included in or exserted beyond corolla tube; anther sacs parallel; anthers dithecal, opening by longitudinal slits. Ovary superior, 2-carpellate; ovules 1 per ovary lobe, placentation basal-axile; style 1; stigmas 2.

Fruit: Nutlets 4; 1-seeded; 0.7–1 mm long; smooth. Seeds with endosperm absent or scanty and oily.

Ploidy: 2n = 18; 36; 48; 64

Habitat: Cultivated and occasionally escaping from gardens; usually in mesic areas.

Elevation Range: up to ca. 1,600 m.